The property possessed by some materials of improving detergency levels of soaps and synthetic detergents and the use of such materials in detergent compositions is known. Such cleaning boosters are called "builders", and such builders permit the attainment of better cleaning performance than is possible when so-called unbuilt compositions are used. While the mechanisms by which builders perform their function are only partially understood, it is known that good builders must be able to sequester most of the calcium and/or magnesium ions in the wash water since these ions are detrimental to the detergency process.
Polymeric acetal carboxylates have been found to be useful as detergency builders. In addition to providing effective sequestration of calcium and magnesium ions, these materials fulfill a need which exists in some geographical areas for effective builders which do not contain phosphorus and which are environmentally acceptable.
Polymeric acetal carboxylate compositions have been disclosed in U.S. Pat. No. 4,144,226 issued Mar. 13, 1979, in U.S. Pat. No. 4,204,052 issued May 20, 1980, in U.S. Pat. No. 4,303,777 issued Dec. 1, 1981, in U.S. Pat. No. 4,315,092 issued Feb. 9, 1982, and in U.S. patent application Ser. No. 627,262 filed July 2, 1984. The use of such polymeric acetal carboxylates in detergent compositions is disclosed in U.S. Pat. No. 4,146,495 issued Mar. 27, 1979. Processes useful in the preparation of such polymeric acetal carboxylates are disclosed in U.S. Pat. No. 4,140,676 issued Feb. 20, 1979, in U.S. Pat. No. 4,201,858 issued May 6, 1980, in U.S. Pat. No. 4,224,420 issued Sept. 23, 1980, in U.S. Pat. No. 4,225,685 issued Sept. 30, 1980, in U.S. Pat. No. 4,226,959 issued Oct. 7, 1980, in U.S. Pat. No. 4,226,960 issued Oct. 7, 1980, in U.S. Pat. No. 4,233,422 issued Nov. 11, 1980, and in U.S. Pat. No. 4,233,423 issued Nov. 11, 1980.
Although the methods for preparation of polymeric acetal carboxylates disclosed in the above patents and patent application are effective in producing such compositions, it has been found that the active yield of the polymer salt obtained by using these methods is less than about 75% of theoretical, based upon the amount of monomeric starting material employed. While "yield" is reported for the amount of polymer product in several of the above patents, these yields were calculated on the basis of the total weight of the solid compositions recovered. When the active yields of the material produced by the procedure of the examples in the patents listed above are calculated using techniques described herein, it is found that the active yield of the desired polymer salt was in each case less than 75% of the theoretical, based upon the amount of monomer starting material employed.
This invention provides a process for production of a polymeric acetal carboxylate with an improved active yield.